1. Technical Field
The present disclosure relates to a speaker device and a vehicle and an AV equipment each including the speaker device.
2. Description of the Related Art
A speaker device is mounted in, for example, a vehicle, AV equipment, a mobile object, or a building. In recent years, demand for reduction in size of a speaker device and a small occupied area of the speaker device has grown. At the same time, demand for high power and wide-range frequency in playback from the small body with low-distortion sound has grown.
In general, if the size of a speaker device is reduced, it is difficult to ensure sufficient sizes of members that support a drive system (e.g., the edge and the dumper) due to the size limitation. Accordingly, the supporting forces of the diaphragms become asymmetrical with respect to the position of the diaphragm having a displacement of zero. Note that the phrase “position of the diaphragm having a displacement of zero” refers to the position of the diaphragm when no drive signal is input to the speaker device. In addition, due to the thickness limitation, the drive forces of the diaphragms may become asymmetrical with respect to the position of the diaphragm having a displacement of zero. The asymmetry property of the diaphragm supporting forces and diaphragm drive forces causes distortion of the playback sound and, thus, prevents the speaker device from being reduced in size and producing high power.
In addition, a speaker device for reducing distortion of the playback sound caused by the asymmetry property of the diaphragm supporting forces and diaphragm drive forces of the speakers and simultaneously reducing vibration of a cabinet has been developed (refer to, for example, Japanese Unexamined Patent Application Publication No. 11-178085).
FIG. 10 illustrates the configuration of an existing speaker device (a speaker device described in Japanese Unexamined Patent Application Publication No. 11-178085). As illustrated in FIG. 10, a speaker device 80 includes a first speaker unit 83 and a second speaker unit 84 fixed to a first opening 85a and a second opening 85b, respectively, and a connection member 86 that connects a first speaker frame 87 to a second speaker frame 88. As a result, vibrations generated by the vibrating diaphragms of the first speaker unit 83 and the second speaker unit 84 are canceled out and, thus, the vibrations of the first speaker unit 83, the second speaker unit 84, and a cabinet 82 can be prevented. In addition, the sum of the drive forces of the diaphragms of the speakers is symmetrical with respect to the stationary position of the diaphragm located during no input and, thus, the second-order distortion of the speaker can be significantly reduced.